I would like to ask what is the best strategy for extracting color histograms and specifically HSV.

In the following workflow I am trying to extract Hue, Saturation and Value like tis:- Multiple Color Image Opener -Global Feature Extraction from Single Image -Color to Grayscale->Grayscale to Color->Histogram (performed 3 times, one for H, one for S and one for V)

I get the exception: Duplicate attribute name Histogram0.

Is this the correct way to extract histograms, or is there something wrong with the workflow?

thank you for the reply and I am sorry for my delay to reply. It is just that I am trying to understand what information do I get. With your workflow but also when I try to extract H,S or V separately the result that I get is 0.001 at histogram62 and 0.999 at histogram63(0..000 and 1.000 when I do only H,S or V).-Does then number of bins even plays a role here? -Why is the result displayed at histogram62 and histogram63 and not in another one?-And finally what does this information tells me about the particular image? If e.g. I extract histograms only for Value and I get 1.000 at histogram63, does this mean that my image is very bright? But for which Hue?

I know that these are understanding questions, but although I understand HSV model I don't understand the information that RapidMiner give me here.

Why is the result displayed at histogram62 and histogram63 and not in another one?

Maybe you have image with only two colors or only similar colors in small range. Try to set histogram bins to 128.

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And finally what does this information tells me about the particular image? If e.g. I extract histograms only for Value and I get 1.000 at histogram63, does this mean that my image is very bright? But for which Hue?

Image is converted to gray scale before histogram is calculated. So in color image it is hard to say. But if you have only hue channel it is the max value of hue.

What I want to do is extract HSV color histograms. My test photo has more than 2 colors and even when I try to extract only one of the HSV channel Iend up having values only on histogram 62, 63. This is either wrong or I don't understand what should the HSV result be.